Brainteaser 1563: Family sum

From The Sunday Times, 23rd August 1992 [link]

In this puzzle digits have been consistently replaced by letters, with different letters being used for different digits. This addition sum then makes sense:

also AND is divisible by three.

What is the number REAGAN?

This puzzle was selected for the book Brainteasers (2002, edited by Victor Bryant). The wording was only slightly changed from the original puzzle.